Glow discharge device



p 1933 H. w. WEINHART 1,926,889

GLOW DISCHARGE DEVICE Filed June 26, 1929 WVENTOI? H. W WE/NHART Patented-Sept. 12, 1e33 1,925,889i j UNITED STATES PATENT OFFICE GLOW DISCHARGE DEVICE Howard W. Weinhart, Elizabeth, N. 1., asalgnor to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application June 26, 1929. Serial No. 373,818

8 Claims. (Cl. 176-122) This invention relates to glow discharge deoperates with the cathode so that the whole of vices and more particularly to devices of this type the plane surface is exposed to permit radiation which constitute an especially eflicient source of of light rays therefrom, the electrodes being enlight. closed within a transparent bulb on container In electro-optical systems, for example, picture filled with neon, argon or other gas or mixture 60 transmission, television, sound recording sysof gases.

tems, etc. a highly concentrated and very bril- For a complete understanding of the invenliant light of great intensity is most desirable. tion, together with its principles, organization It has heretofore been proposed to utilize glow and mode of operation, h f owing descripdischarge devices as a source of light in systion should be read in conjunction with the 65 tems of the type described above and to give at attached drawing. least one of the electrodes such configuration that 1 is a Side elevation of a Structure which the light produced by the glow discharge is highly embodies the invention with a portion of the concentrated and of considerable brilliancy. bulb broken aw y to ow t e relation of the In an article entitled Die Stromdichte des Parts Of the d v 70 normalen Katodenfalles" by Gunther-Schulze, 2 is Cress-Section 0n the line of which appeared in Zeitschrift fiir Physik in 1923, 1; and it is explained on page 315 that in order to pro- 3 is a Perspective Vi w illustrating h duce a cathod potential drop whi h i uniform anode and its relation to the plane surface of the with respect to the cathode surface of a glow cathode. 76 lamp it is essential that the anode completely Referring to 1 there is h w a 8 w surround the cathode andbe uniformly spaced charge device comprising a ansparent bulb or therefrom, container 1 having integrally formed therewith An experimental apparatus for effecting the a stem 2.

above sult is shown in Fig. l on page 315. This Mounted upon the stem 2 and sealed thereto is a 80 apparatus comprises a platinum cathode consticathode 3 of conductive material. p a y tuting an elongated thimble with its upper end pp The pp r cathode 3 may be sealed closed by a rubber stopper which carries an into the stem 2 in any app v d ma n r. f r exlet tube and outlet tube through which water is p as disclosed in Patent 9 6 30 supplied to the interior of the platinum cathode, issued Februa y 8, 1919 to Hellskeeperan anode of iron wire netting positioned con- Ca d 3 wh su stantially ylindrical and centrically of the cathode and an enclosing bell sed a O e e d 4 is either flattened D jar of 5.5 liters capacity which is mounted on a vid d with a p a su a 5 extending a ia ly brass base and sealed thereto with grease and thereof.

35 mercury. In this construction the negative glow The anode 6, which may be fork-shaped, is completely surrounds the cathode and extends upp t d pa a l l t the flatt d or plan su from one end of the tube to the other and hence face of the cathode 3. The tines of the fork is of relatively large area. shaped anode are preferably of the same length An object of the present invention is to proas the plane surface 5 and respectively lie in 40 vide a glow lamp having an extended plane glow planes which define the periphery of that surarea which radiates light of uniform intensity face. The anode is supported from the stem 2 throughout and the operation of which is stable. by conductors '7, each enclosed in a glass sleeve Another object is to provide a light source of 8, having their opposite ends secured to a collar very high intensity and extreme brilliancy. 9 mounted on the stem 2.

45 One embodiment, which will be hereinafter The plane surface 5 is surrounded by a recdisclosed whereby the above mentioned and other tangular insulating plate 10, which may be of objects are accomplished, involves a substantially lavite, and the remainder of the external surcylindrical cathode having one end closed and face of the cathode is covered with an insulating the opposite end carried by a stem provided with cement 11. In other words, the whole surface of 50 a stopper carrying an inlet tube and outlet tube the cathode, except the plane surface 5, is com-: extending into the cathode through which a coolpletely insulated, as is also the sleeve or collar ing fluid is supplied to circulate therein and havto which the anode leads are connected. ing one face flattened to provide a plane surface; The cathode 3 and anode 6 are provided with a fork-shaped anode with its tines parallel to lead-in wires 12 and 13 respectively, which ex- 5 the periphery of the cathode plane surface, 00- tend through the stem 2 and wall of the constainer 11 1 for connection to contacts mounted on a base (not shown) of the type now generally used in the manufacture of incandescent lamps. The portion of the anode lead-in wire between the collar 9 and the wall of the glass container is enclosed in a glass sleeve 14.

Intermediate between the stem and the electri cally active surfaces of the anode and cathode is a mica disc 15 of the same diameter as the interior of the bulb 1.

The lavite plate 10 is provided with an opening which corresponds exactly in shape and size to the plane surface 5 of the cathode. The external dimensions of the lavite plate are such that, at the operating potentials applied to the device, the electric discharge from the anode to the cathode is confined to surface 5. The quartz cement 11, which is composed of powdered quartz and sodium silicate, and the glass sleeves 8 and 14 are provided to prevent the occurrence of electric discharges to or from the leads 7, 13 and collar 9.

As an additional precaution, to prevent electrical discharges through undesired paths within the bulb, the mica disc 15 is'provided to divide the interior of the bulb into an active discharge area and an inactive section.

The stem 2, which is hollow, is closed by means of a rubber plug or stopper 16, through which extends an inlet tube 17 and an outlet tube 18. A cooling medium, for example, water is supplied to the interior of the cylindrical cathode 3 through the tube 17 and after traversing the surface of the cathode is discharged through the tube 18.

The cathode 3 is of copper, and the active surface 5 is plated with a material which tends to reduce sputtering. This material may be either nickel or beryllium.

After the structure described above is completed it is evacuated and then filled with a gas water vapor to reduce the operating voltage of the device.

All glow discharge devices hereinbefore produced have been subject to very definite operating limitations. One of the important limiting factors has been the fact that there is an optimum current density which may be used in any given device without causing overheating of the cathode, whereby undesirable gases may be released. Again overheating of the cathode may result in the production of an electronic discharge, which would provide a current conductive path across the dark space surrounding the cathode and result in a reduction of the intensity and brilliancy of the negative glow.

The present invention by providing means for dissipating the heat generated at the cathode increases the current carrying capacity of the tube and thereby causes,the intensity and brilliancy of the negative glow to be materially increased. The degree to which the dissipation of the heat may be carried is limited solely by the capacity of the cooling medium to conduct away the heat and will be determined largely by the rate of flow of such medium through the cathode.

'Confining the current discharge from the anode to a plane surface, constituting a limited portion of the cathode area, results in the production of a negative glow area commensurate with the plane surface and having high current density. By the use of a fork-shaped anode it is possible to so position the glow discharge device that the whole surface of the negative glow area is viewed at a small angle with respect to the axis of the bulb, so that the light rays, emanating therefrom, may be concentrated in a small area corresponding to a rectangle bounded by the ends of the tines of the fork-like structure. Thus there is provided a high degree of concentration of the light rays emanating from the negative glow discharge area.

The bulb 1 is provided with a spherical portion, which is materially larger than its cylindrical portion, through which the negative glow is viewed. Two important results followed therefrom, namely, the field of vision along the length of the glow discharge is materially increased and loss of light intensity, due to the deposit of sputtered material on the inner surface of the spherical viewing portion of the bulb is avoided. This is due to the fact that the deposition of sputtered material occurs along the interior surface of the bulb which lies parallel to the plane surface of the cathode, rather than upon the extended spherical portion.

While one specific modificationof the invention has been described and certain features have been set forth in detail, it is to be understood that the invention is not limited to the details herein given.

Obviously the ends of the tines of the forklike anode could be connected together to provide an anode having an active surface which is rectangular. Again in small discharge devices v the anode may be supported by a single lead wire, a portion of which may be wrapped around the stem to replace the collar 9.

' What is claimed is:

1. A glow discharge device comprising a forkshaped electrode, a hollow electrode having a plane surface parallel to the plane of said forked electrode, means for producing an electric discharge between said forked electrode and plane surfaces, and means for circulating a cooling medium through said hollow electrode.

2. A glow discharge device comprising a forkshaped anode, a hollow cathode having a plane surface, means for producing an electric discharge between said anode and said plane surface, and means for circulating a cooling medium through said cathode.

3. A glow lamp comprising electrodes lying in parallel planes between which a discharge is maintained, and an enclosing bulb having a portion the wall of which surrounds said electrode and is substantially parallel therewith and an extension the wall of which is at an angle to the plane of said electrodes.

4. A glow lamp comprising a plurality of electrodes, means for mounting said electrodes parallel to each other, and an enclosing bulb having a portion thewall of which surrounds said electrodes and is substantially parallel therewith and a substantially spherical extension.

5. The combination with a containing vessel a portion at least of which is transparent, of a gas filling within said vessel, means for ioniz ing said gas to cause it to glow in a restricted region, all parts of which lie near to or in a plane, said means comprising two electrodes, one of which is hollow and has an extended plane surface and the other of which has two separated portions near to and substantially parallel to said plane surface, said region of ionized gas lying between said portions, and means for circulating a cooling medium through said hollow electrode.

6. The combination with a containing vessel a portion at least of which is transparent, of a gas filling within said vessel, means for ionizing said gas to cause it to glow in a restricted region, all parts of which lie near to or in a plane, said means comprising two electrodes, one of which is hollow and has an extended plane surface and the other of which has two separated portions near to and substantially parallel to said plane surface, the distance between said portions being much greater than their effective length, said region of ionized gas lying between said portions, and means for circulating a cooling medium through said hollow electrode.

7. The combination with a containing vessel 2. portion at least of which is transparent, of

v a gas filling within said vessel, means for ionizplane, said means comprising two electrodes one of which is hollow and has an extended plane surface and the other of which is adjacent thereto and has an opening defining said region, and means for circulating a cooling medium through said hollow electrode.

8. The combination with a containing vessel a portion at least of which is transparent, of a. gas filling within said vessel, means for ionizing said gas to cause it to glow in a restricted region, all parts of which lie near to or in a plane, said means comprising two electrodes one of which has an extended plane discharge portion and the other of which has a discharge portion closely adjacent the periphery of said plane discharge portion, and an enclosure within said vessel, opening externally thereto, for the circulation of a cooling medium to cool said plane discharge portion.

HOWARD W. WEINHART. 

